Development of Effective Rockfall Barriers

As a part of the construction of Interstate 70 through Glenwood Canyon, in Colorado, three new types of barriers for protection against rockfall were developed through a program of prototype testing, numerical simulation of rockfall events, and analysis of barrier response to impact by boulders. New barriers include a suspended pendulum system that attenuates the kinetic energy of falling boulders, a flexibly mounted fence of steel cables and mesh, and a free-standing mechanically stabilized earth wall. The capacity of rockfall barriers, stated as a limiting translational kinetic energy of falling boulders, ranges from 41 kJ (30,000 ft$\dot{s}$lb) for light fences to more than 1,400 kJ (1,000,000 ft$\dot{s}$lb) for mechanically stabilized earth walls. Earth walls can halt falling boulders that weigh as much as 13,700 kg (30,100 lb). The three barriers reported here are useful as options to ditches, berms, rigid fences, and rigid walls of rockfall protection for highways. This paper provides a summary of barriers developed in Colorado, a summary of associated numerical simulation and analytical tools developed specifically for the barriers, as well as a guide to more detailed information on development and testing programs for rockfall barriers.